The Environmental Protection Agency has granted a financial hardship waiver to an oil refinery owned by billionaire and former Donald Trump advisor Carl Icahn, according to reports. Reuters reported that the move will allow Icahn’s Oklahoma facility to avoid tens of millions of dollars in costs related to the U.S. Renewable Fuel Standard (RFS) program. Icahn stepped down from his position as special regulatory adviser to Trump last August after lawmakers cited potential ethical problems in his dual role as an adviser and an investor. The billionaire is under investigation by the U.S. Department of Justice for his role in influencing biofuels policy while serving as Trump’s adviser. “This one’s going to be hard for [Scott] Pruitt to explain,” Brooke Coleman, head of the Advanced Biofuels Business Council industry group, said in an email Friday, referring to the under-fire EPA administrator. The refinery was denied exemptions by former President Barack Obama’s administration, federal filings showed.